Image Processing Apparatus, Image Processing Method, and Distortion Correcting Method

1. An image processing apparatus comprising a distortion correcting unit for sequentially performing distortion correction processing in units of block image data obtained by dividing an image data, the image processing apparatus further comprising a distortion correction range calculating unit, separate from said distortion correcting unit, for calculating an input image range necessary for distortion correction processing performed on the block image data by the distortion correcting unit, wherein the distortion correction range calculating unit comprises: a coordinate generating unit that generates interpolation coordinates corresponding to pixels in a coordinate system of the image data after distortion correction processing; a distortion-correction coordinate transforming unit that applies a predetermined distortion correcting formula to the generated interpolation coordinate for transformation into coordinate positions of pixels in the coordinate system of the image data before distortion correction processing; and a correcting range detecting unit for calculating the input image range necessary for the block image data in the image data before distortion correction processing from the transformed coordinate position, wherein the distortion correction range calculating unit calculates the input image range for distortion correcting processing on a next block of image data concurrently with execution of the distortion correcting processing of a block of image data preceding said next block of image data by the distortion correcting unit.

2. The image processing apparatus according to claim 1 , wherein the coordinate generating unit generates the interpolation coordinates by using only coordinate positions corresponding to pixels of a peripheral portion of a side of an output image range after distortion correction processing.

3. The image processing apparatus according to claim 2 , wherein a shape of the output image range is rectangular, and the coordinate generating unit generates the interpolation coordinates by using only coordinate positions corresponding to pixels of four sides of the rectangular output image range.

4. The image processing apparatus according to claim 3 , wherein the distortion correction range calculating unit calculates the input image range based on at least one of maximum and minimum values of the coordinate positions of the pixels corresponding to the four sides of the rectangular output image range and coordinate positions corresponding to pixels of four vertexes of the rectangular output image range, with respect to the coordinate positions generated by the coordinate transformation.

5. The image processing apparatus according to claim 1 , wherein the distortion-correction coordinate transforming unit performs the calculation included in the predetermined correcting formula on time-series data.

6. The image processing apparatus according to claim 1 , wherein the coordinate generating unit obtains interpolation coordinates by performing predetermined thinning-out processing with respect to the interpolation coordinates for distortion correction processing.

7. The image processing apparatus according to claim 1 , wherein the distortion correcting range calculating unit calculates the input image range by sequentially repeating the input image range calculation with respect to a plurality of input signals for distortion correction processing.

8. The image processing apparatus according to claim 1 , wherein the input image range calculation is performed repeatedly, and a correcting magnification M is determined such that an image range after distortion correction processing comes within a predetermined range with respect to the input image range.

9. The image processing apparatus according to claim 7 , wherein the input image range calculation is performed repeatedly, and a correcting magnification M is determined such that an image range after distortion correction processing comes within a predetermined range with respect to the input image range.